Composite structures formed from metal decking on which a concrete slab is cast are commonly used in building. Typically, the decking is installed on site so as to span supporting elements, such as columns or walls. The decking includes a pan section and upstanding edge regions which are in abutting relationship so as to form a continuous surface. Concrete is cast over the surface so that the upstanding edges are embedded in the slab. The metal decking therefore acts both as formwork for casting of the slab, and also provides tensile strength to the structure on curing of the slab.
In the applicants' earlier International applications, PCT/AU01/01446, and PCT/AU01/01447, an improved metal decking is disclosed which incorporates a precamber in the longitudinal direction of the decking. The purpose of the precamber is to compensate for deflection of the decking on casting of the slab thereby enabling the decking to span greater lengths without exhibiting excessive deflection of the composite structure. The decking in these earlier applications also discloses an improved edge interlock arrangement which further improves the strength of the composite structure.
Whilst metal decking according to the above form has improved performance, difficulties have been encountered in incorporating the precamber into the metal section.